Natural products and their derivatives continue to play an important role in the drug pipeline. Over time, 7000 known structures have led to more than 20 commercial drugs, and about half of the new drugs approved in the last decade are based on natural products. Screening of new natural products and their analogs will continue, and be enhanced by modern methods such as metabolic engineering, synthetic biology, and structural analysis of compounds and the enzymes that produce them. For example, new biosynthetic routes are being built around engineered systems such as the modular polyketide synthases to produce new compounds. There are also still a tremendous number of new microbial natural products to be explored, as evidenced by the genomic sequencing data coming forth. Nevertheless, the discovery of new compounds remains an adventitious endeavor. Genome mining efforts to identify interesting clusters and to predict what natural products might come from these clusters of genes are beginning to produce hypotheses; however the homology of the enzymes to known enzymes is generally low. We propose to create a new partnership, named the Natural Products Partnership, within the PSI Biology Network framework to play strong joint roles in both the identification of new natural product pathways and the subsequent discovery of new natural product-based pharmaceuticals by revealing the structures and active sites of novel enzymes, characterizing the enzymatic reactions of the gene products, identifying new natural products and thus offering opportunities to identify and customize the pathways by altering specificities and/or identifying novel proteins or domains with desired enzymatic properties. The combination of the PSI Network Centers with their high-throughput structure determination capability and the biology-driven team of natural products scientists through the Natural Products Partnership are strongly positioned to create a high impact program. The experience of the structural biologists with PSI activities and their leadership in developing technologies and infrastructure in the PSI program will make a smooth transition to PSI Biology activities possible.